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H. 0. GOODRIGH.

TENSION DEVICE FOR SEWING MAOHINES.

No. 81,080. 4 Patented Aug. 18 1868.

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HARRY 0. GOODRIGH, OF CHICAGO, ILLINOIS.

Lean-s Patent o. 81,080, dated August 18, 1868.

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TO ALL WHOM MAY- CONCERN:

Be it known. that I, HARRY C. GOODRICH, of Chicago, in the county of Cook and State of Illinois, have invented a new.,an d useful Self-Adjusting Tension-Device for Sewing-Machines and I do declare that the following is a full, clear, and exact description'of' the same, reference being bad to the accompanying drawings, making a part'of this specification, in which-- Figure 1 is a back view of a sewing-machine with my device, marked Figure 2, attached.

Figure 3, an end view of the device, ready'fo'r attachment.

Figure 4, a top view.

Figure 5, a detached view of the upper plate.

It is well known that in usin' g sewing-machines, the required tension of thethread depends upon the thick- S- ofth'efabric to be S W nd .t dt the operator, to'do good work, must adjust the tension of the thread as often as there is a. change iii-the th nes's'oflth'e work,' w'hethcr such change be occadioned by-the use of fabrics ofldilferent thickness,'or by varying the number-of layers or thicknesses of cloiilf in the machi-neya'nd the" objected my invention is rt provide a tension-devicewhi'ch shall be self-adjusting,.as hereinafter described. Td enable others skilifed in the art to make and use my invention, I proceed to describe the construction and operation of the device. i

s A is a plate, about three-fourths of ohe inch wide, and about one inch long, having also an extension, 11, v at one end. This plate may be of metal, glass, or any other suitable material, and its upper surface is perfectly smoothr It is permanently attached to the clasp or body B. G is another plate similar to the one described,

having its under surface smooth, with a countersink, b, in the centre of the upper surface, One edge of this L plate may have a -fianch, a, to keep it in position; dis a hook or other suitable'device, 'to' receive the thread before it is passed between the two pressure-platesA C. e is a groovc in the extended part of the under plate A, in which the thread passes. The plate C is of the same size as A, without the extension. D is a spring, pivoted atf upon a pivot attached'to the extension a. One end of this spring rests upon g, a projection from the bar or rod to which the pressure-foot.is attached, and the other end is provided with a female screw, it, to receive the screw 2', the lower end or point of which rests in the countersink b in plate U. My deviceissecured to the arm E, being the pressure-foot arm, by means of the thumb-screw as shown in fig. 1.

In operation, the thread is passed from the spool through the guide d, then between the plates A C,-and from the plates to the needle, in the usual manner. The-tension of the thread is then to be adjusted to asingle thickness of the fabric to be sewed, by the use of the screw 2'. The device is .then ready for use.

' If new one or; more additional layers or thicknesses of cloth be passed between the pressure-foot 7c and th feed I, the tension of the thread must be correspohdingly increased, because the spring D, arranged as described, is in fact a lever, having its fulcrum at a, the end ofthe long. arm resting on thepressure-foot rod or bar at g, and the short arm practically resting on the plate 'l at c. When, then, the thickness of the work is increased, the long arm' of the lever is raised, and the pressure of the plate 0 upon the thread is increased. If the thickness of the work be diminished, the pressure upon the thread will he diminishedf I thus have a self-regulating tension-device, simple in construction, and sure in operation.-

i The plate A may be permanently attached to or made part of the arm E. It is evident that the lever or spring may be pivoted at the other end of the plate A, the point of the screw remaining in the position before described. When so arranged, the tension of the thread must be first adjusted for the greatest thickness likely to be used, and if that bedecreased, the tension will be correspondingly decreased, the device remaining self adjusting as before.

The spring D should not be very stiff, and the degree of stiii'ness required will depend somewhat upon the machine to be'used, and the relative length of the two arms of the lever; it may be straight or curved. A lever having no elasticity may be used,.if it be made to rest upon a spring attached to the bar or rod to which the pressure-foot is attached- This will not change the principle of my device. In the case lastmentioned, a

coil-spring might be used, attached to the pressure-foot rod or bar, and made adjustable. I

My. device may be used either with single or double-threaded machines, but with the latter only the upper thread will be self-adjusted. 1

Having thus fully described my invention, what I claim as new, and desire to secure by Letters Patent, is The plates A and O, 'in combination with the pivoted spring or lever 1 and set-screw z, construeted and arranged toioperete with the resser-shank, substantially as specified.

v IiARRY '0. eoonmon. Witnesses v E. A. WEST, ALBERT H. -ALLEN. 

